1. Field of the Invention
The present invention relates to an organic/inorganic hybrid material, and in particular relates to an organic/inorganic hybrid material having an inorganic network structure.
2. Description of the Related Art
Organic/inorganic hybrid materials consisting of a combination of an inorganic material and an organic phase combine the properties of organic and inorganic materials. Inorganic materials such as glass, fiber, clay, and carbon black are typically added to an organic polymer as a filler or as a reinforcing agent to improve physical properties and reduce production cost. The effectiveness of inorganic filler is generally determined by the degree of dispersion of the inorganic filler in the polymer matrix. By conventional mechanical blending, only a micro-scale dispersion of the inorganic filler can be achieved and the improvement in physical properties is limited. Using the novel organic/inorganic nano-hybrid technique, inorganic filler can be dispersed in the organic matrix in a nano-scale, greatly improving physical properties due to the greater contact surface between the organic phase and inorganic phase. The nano-hybrid material is characterized by high transparency, high thermal resistance, low coefficient of thermal expansion, and excellent mechanical properties. In order to increase the physical properties, the key issue in developing hybrid materials is to increase the amount of inorganic filler present in the hybrid.
Japanese Patent Publication no. 2005187768 discloses a polyimide/inorganic composite material having a silica content up to 20 wt %. Polymer Bulletin 51. 63-68 (2003) discloses the synthesis of polyimide/silica hybrid via a sol-gel route, wherein polyimide and silica are connected by a coupling agent with covalent bonds. The hybrid films thus obtained can keep their transparency at up to 40 wt % silica content. However, when the silica content is greater than 40 wt %, silica particles will agglomerate due to insufficient polymer content, resulting in opaque, brittle films.
Accordingly, it is highly desirable to increase the inorganic content to improve the physical properties while maintaining the transparency and flexibility of the organic/inorganic hybrid materials.